Shea butter is scraped from a bowl into a plastic container
Processed shea butter (Wikimedia/ Daveynin)

Amid heightened attention to systemic racism and the Black Lives Matter movement, a new paper by University of Guelph researchers discusses the intertwined but forgotten history of African food crops and slavery in the West, and points to potential uses of those crops to help mitigate climate change impacts.

The paper offers the first interdisciplinary review of how crops migrated alongside slaves taken from Africa to America, said Emily Sousa, lead author and a master’s student in the School of Environmental Design and Rural Development.

It also proposes that many largely overlooked foods, including cereals, yams and okra, hold “untapped potential” to help ensure global food security and sustainable development.

Written with plant agriculture professor Dr. Manish Raizada, the study appears in Frontiers in Sustainable Food Systems.

Sousa’s interest in the topic stems from Raizada’s undergraduate class in plant agriculture for international development that exposed stereotypes about food security in many African countries. “Africa is studied more for crises in food than what it has to offer,” she said.

Emily Sousa
Emily Sousa

Combining history, social science and plant science, the paper highlights historical aspects of these crops as well as their future potential.

“It’s important to recognize that a lot of racism and oppression was involved in how these crops got there,” said Sousa.

Today, more than 3.2 million hectares of watermelon are grown worldwide; it’s the second highest fruit crop by weight produced globally. Originating in West Africa, it was long associated with racial stereotypes and racial injustices in the United States.

“Most of us are probably unaware that we have ancient African farmers to thank for this food, along with coffee, Coca-Cola and Palmolive soap,” said Sousa. “We hope that recognition of such contributions will bring pride to peoples of African ancestry.”

Palm oil mixed with other ingredients was fed to sustain slaves during the Middle Passage across the Atlantic. Along with “shea butter” from sub-Saharan Africa shea trees, palm oil was also rubbed onto the skin of enslaved African peoples to make them appear younger to potential buyers.

Sousa said learning about such practices, while unsettling, was important for her research. “To address systemic racism, you have to have uncomfortable conversations and review unfortunate histories and understand their connections to the present.”

Many transplanted crops grown on slave plantations became part of African American “soul food” – often seen as a form of resistance against racial oppression — and contribute to American cuisine today.

Prof. Manish Raizada

Leafy greens used in soul food like kale, collard greens and chard were not indigenous to Africa but were introduced to the Americas from Europe through the slave trade. Okra from West Africa was used in gumbo (gumbo means “okra”) stews that are part of southern Creole food culture.

The U of G paper also highlights the potential uses of African food crops to improve global food security, alleviate poverty and mitigate climate change impacts.

Cereals including sorghum, millets, fonio and teff contain many nutrients and are adapted to drought conditions. Yams are also nutrient-rich and can be left in the ground year-round until needed, useful in poor countries lacking post-harvest cold storage. Known as the “perfect villager’s vegetable,” okra is nutritious and thrives despite environmental stresses.

Sousa said Africa holds untapped genetic diversity in food crops that could be used to improve nutrition, alleviate rural poverty, provide genetic stocks for breeding for desired traits, and help mitigate environmental impacts of farming.

“It’s important that African nations and local communities possess full control over their genetic resource and not be further exploited,” she said.

Cowpeas, also called black-eyed peas, use nitrogen-fixing bacteria to make their own fertilizer. “This prevents us from having to use fossil fuels to make synthetic nitrogen fertilizer,” said Raizada.

Colocynth on a vine in the sand
Colocynth in Adrar desert, Mauritania (Ji-Elle/Wikipedia)

Grown alone or intercropped with corn and wheat, watermelon plants are drought-tolerant and help suppress weeds. That can benefit developing nations where smallholder women farmers can spend half their time hand-pulling weeds.

Many development projects in sub-Saharan Africa have centred around shea trees, which provide nutrients and medicinal treatments and help maintain livelihoods for women producers.

For her research, Sousa pored over online archives, including looking at cookbook recipes. One handwritten letter written by a white settler referred disparagingly to slaves’ use of yams. “It was heartbreaking to hear the way people were objectified in these letters.”

Raizada recommended crops to investigate and looked at their genetics and domestication in Africa. He said West Africa should be recognized as a “hot spot” for domestication of crops rivalling ancient Mesopotamia and Mexico.

Particularly during protests this year after George Floyd was killed during his arrest in Minneapolis, Sousa questioned whether she should be studying this topic as a “white, settler researcher.” But looking at the origins of food crops offers an important, little-studied view into a controversial issue.

“We may be unaware of African origins and trauma that have brought these crops to our plates and tables today,” she said.

“But acknowledging these histories, even in agriculture and agri-food, remains important for the reparation and reconciliation necessary. We all have a role in addressing systemic racism. I can use my privilege and position to amplify Black voices and stories that need to be heard.”


Prof. Manish Raizada